neuroticism vs mental disorder

neuroticism and mental disorder both are nouns.

Word	Noun	Adjective	Verb	Adverb
neuroticism	Yes	No	No	No
mental disorder	Yes	No	No	No

As nouns, mental disorder is a hypernym of neuroticism; that is, mental disorder is a word with a broader meaning than neuroticism:

neuroticism: a mental or personality disturbance not attributable to any known neurological or organic dysfunction
mental disorder: (psychiatry) a psychological disorder of thought or emotion; a more neutral term than mental illness

Other hypernyms of neuroticism include disturbance, folie, mental disturbance, psychological disorder.

neuroticism (noun)	mental disorder (noun)
a mental or personality disturbance not attributable to any known neurological or organic dysfunction	(psychiatry) a psychological disorder of thought or emotion; a more neutral term than mental illness